1. Field of the Invention
This invention relates to curable compositions capable of yielding silicone rubber elastomers by curing. More particularly, the invention relates to cured silicone rubber elastomers having hydrophilic properties or water-swelling properties on the surface thereof and also to curable compositions therefor.
2. Description of The Prior Art
As is well known in the art, silicone rubbers have good weatherability, releasing properties and water repellency and, thus, have utility in the fields of sealants, adhesives, releasing agents, templating agents and waterproofing coating agents. However, where the silicone rubbers are employed as a sealant or waterproofing coating agent, there arises a problem from the standpoint of appearance in that although the silicone rubbers exhibit good weatherability and waterproofing properties, not only they are liable to be deposited with dust and dirt, but also rainwater is readily repelled and is left as droplets on the surface of the silicone rubber. If dried as it is, the rubber surface is covered with spots or stains, with a poor appearance.
On the other hand, since silicone rubber has good releasing properties, it is employed as a dental impression agent. The impression agent is used in the mouth. The use of water-repellent silicone rubber makes it difficult to form an accurate copy of a complicated object or shape. Thus, it becomes essential to rely on dentist's technique for the accurate copying. Accordingly, there is a strong demand for development of silicone rubbers having hydrophilic properties.